1. Field of the Invention
The present invention relates generally to magnetic heads that are utilized with thin film hard disk data storage devices, and more particularly to the design and fabrication of a magnetic head having an improved second magnetic pole including a coplanar P2 pole tip and pole yoke.
2. Description of the Prior Art
In the process for fabricating magnetic heads for hard disk drives, thousands of magnetic heads are simultaneously fabricated in rows and columns across the surface of a substrate wafer, and it is a processing consistency goal that each of the magnetic heads be virtually identical. One of the most important magnetic head parameters is the width of the base of the pole tip which determines the track width that data bits will be written by the magnetic head. Therefore, process consistency in identically forming the width of the base of the pole tip of each of the magnetic heads is very important in obtaining acceptable throughput in fabricating the magnetic heads.
In the magnetic head pole tip fabrication process that pertains to the present invention, one of the many fabrication steps in forming the pole tip is an ion milling step, which is conducted following the fabrication of the pole tip in order to notch a magnetic pole that is disposed beneath to the pole tip. This notching process is well known and understood by those skilled in the art. When the pole tip is fabricated, it is formed with a thin neck, a large anchor piece on one end of the neck, and a large yoke interconnect piece at the other end of the neck. Significantly, during the ion milling notching step, the large pieces at the neck ends have been shown to produce a shadowing of the milling ions during the notching step. As a result, the width of the neck will vary between the two large end pieces, being generally narrower in the more exposed central portion of the neck and wider in the portions of the neck that are shadowed by their closeness to the large end pieces.
The variation in the width of the neck of the pole tip is undesirable in that it results in a variation of the width of the pole tip base throughout the many magnetic heads that are simultaneously formed on the substrate. The present invention is a method for achieving process uniformity of the pole tip width throughout the many magnetic heads that are fabricated across the surface of the substrate.